Flexible shaft



Sept. 9, 1941. w UHLER 2,255,234

FLEXIBLE SHAFT Filed June '7, 1938 INVENTOR ATTORNEY Patented Sept. 9, 1941 FLEXIBLE SHAFT Wilmer P. Uliler, Tottenvllle, N. Y., assignor to The S. S. White Dental Manufacturing Commy, a corporation of Pennsylvania Application June r, 1938, sci-m No. 212,239

mins.

My invention relates particularly to that class of flexible shafts that are formed by coiling or twisting together a plurality of strands of wire either wound closely about a core formed of one or more strands, or so wound as to provide an axial hollow therein, and preferably coiled in multiple pitch relation, and is especially directed to the terminals of the individual cut lengths of the shafting thus formed, which not only serve to prevent uncoiling of the coils of the shaft, but

which may also afford a convenient means of attachment of the driving and driven elements of associated mechanism which said shaft is adapted to operatively connect.

It has heretofore been common practice in the manufacture of flexible shaftlng, particularly when severing the cut lengths to form individual operative shafts, to prevent the uncoiling or separating of the coils of the shaft structure, by the application of solder or by brazing the region adjacent to the extremities of the individual shaft lengths to which a suitable fitting may be conveniently secured to provide an attachment for the connecting elements.

The more recent mode of preparing the shafting manufactured in long lengths has been to swage the shafting at relatively spaced predetermined regions to provide a substantially solidified rigid section through which the shafting may be severed transversely without danger of unravelling of the component strands or wire caused by the accidental and detrimental displacement of the individual strands; The squared or otherwise polygonal terminals thus formed, having a plurality of flat surfaces, may be used to afford means unitary with the flexible shaft structure to engage similar or suitably shaped sockets in the driving and driven elements of the mechanisms to be connected by said shaft, thereby eliminating the necessity for applying a specially made fitting to the shaft terminals.

I have found in practice that the operation of swaging the flexible shafting to provide polygonal terminal regions serves as a highly efficient medium for effectively maintaining the strands of the smaller sizes of shafting intact and affording an ideal means for attaching the shafts to the driving and driven elements of the devices to be connected. 7

However, in shafting of the larger sizes wherein the diameters of both the shaft structure and the individual strands which make up said structure are increased, the pressure required to emregions so increases as to become uneconomical and practically not feasible to commercially produce such terminals.

The principal objects of my invention are to provide flexible shaftingwith relatively spaced regions so swaged as to prevent the accidental displacement of the strands of which the shaft structure is formed.

Other objects of my invention are to provide a flexible shaft of any desired dimensions with solidified rigid terminal regions that may be economically formed by swaging to afford satisfactory and highly eflicient means for engaging suitably shaped sockets in the connecting ele- 15 ments of driving and driven devices adapted to be coupled.

Further objects of my invention are to provide the terminal regions of a flexible shaft with a plurality of longitudinally extending flutes which afford a corresponding number of elongated teeth and which so efliciently crimp the individual strands as to prevent their relative separation or displacement from those immediately adjacent whereby a substantially solid rigid terminal structure is formed.

My invention includes a flexible shaft having its terminals so formed as to provide longitudinally extending teeth having side surfaces so closely approaching parallelism with diametric planes coincident with the axis of the shaft structure as to afford direct pressure contact with the corresponding cooperative. surfaces of the socket into which the shaft terminal is to be entered.

My invention comprehends a flexible shaft having its terminals formed to provide teeth serving as a pinion that may conveniently cooperate with an associated gear or train of gears as may be desired to transmit rotary motion thereto. The form of the indentations and teeth might be varied to obtain best tooth forms for the purpose.

The form of my invention as hereinafter described, comprises shafting preferably fabricated in continuous length, and having regions at predetermined distances apart, swaged to provide a plurality of flutes extending longitudinally of the shafting structure and preferably equally spaced circumferentially to form projecting teeth whose circumferential surfaces are substantially coincident with the outer surface of said shafting structure, the formation of said flutes and the teeth incidentally produced serve to so crimp and compress the individual strands into an inert ciently deform into polygonal shape the terminal mass that the shafting may be readily cut through the swaged region to provide individual shaft lengths without incident relative separation of the composite strands.

My invention also includes all of the various novel features of construction and arrangement as hereinafter more deflnitely specified.

In the accompanying drawing, Figure l is a fragmentary side elevational view of a continuous length of coiled wire flexible shafting swaged at predetermined distances apart to form longitudinally disposed circumferentially arranged flutes in accordance with my invention; Fig. 2 is an enlarged fragmentary side elevational view of the end portion of a cut length of the shafting shown in Fig. l which has been severed through the swaged region, and which aflords a fluted swaged terminal tip; Fig. 3 is a transverse sectional-view of the flexible shaft shown in Fig. 2, taken through the flexible shaft structure on the line 3--3 in said Fig. 2; Fig. 4 is a transverse sectional view of the flexible shaft shown in Fig. 2, taken through the fluted terminal region on the line 4-4 in said Fig. 2; Fig. 5 is an end elevational view of the shaft shown in Fig. 2; Fig. 6

is an end elevational view of the fitting element of a driving or driven device into which the fluted terminal region of the flexible shaft shown in Figs. 2, 4, 5 and 7 may be inserted for operative connection; and Fig. 7 is a conventional perspective view of the end portion of the flexible for engaging suitably formed sockets It for connecting the shaft to driving and driven elements I! or devices. It is also obviou that the swaged region may be conveniently employed as a pinion,

the teeth l2 thereof being capable of cooperating with the teethof suitably arranged gears not shown, but which may cooperate with the teeth shaft as shown in Fig. 2, the lines of the in- 'dividual strands being omitted for convenience of illustration.

'In said figures, the shaft as shown is formed by coiling together severallayers of wire strands l, 2, 3 and 4 in alternately opposite directions about a wire strand mandrel or core 5, whereby continuous or long lengths of flexible shafting may be fabricated, from which cut lengths for commercial purposes may be severed.

As illustrated in Fig. 1, the fabricated shaft is swaged at predetermined distances apart to provide fluted regions 5 and 1 formed by swaging a plurality of longitudinally extending grooves or troughs l0 suitably spaced circumfercntially about the outer cylindrical surface of the shaft structure and of a depth sufficient to crimp not only the wire strands l of the outer layer, but to similarly effect crimping of the under layers 2, 3 and 4, the latter preferably being forced to bite into and indent the core or mandrel 5.

The swaging operation tends to so crimp, mash and crush the wire strands of the swaged region into such a compact mass as to distort and interlock them and cause them to cling together and remain inert and render the swaged region rigid and substantially solidified without the use of solder or other binding agents or devices.

The shafting .thus produced may be conveniently severed into commercial shaft lengths by cutting through the swaged solidified fluted regions 6 and I on the dot-and-dash lines 8 and 9 without danger of accidental separation of the wire strands of which the shaft structure is composed.

The swaging of the shafting to form the grooves or troughs l0 incidentally forms the interposed ridges or teeth I! whose outer restricted cylindriform surfaces preferably are substantially in cylindrical alinement with the peripheral surface of the flexible portion of the shaft structure I! which extends between the swaged terminals l5.

Thus it will be obvious that the swaged terminals I! will be capable of being readily threadi2 of the terminals or with teeth swaged at any part of the shaft intermediate of its terminals, as may be desired.

My invention is advantageous in that the individual strands that make up the shaft structure may be so crimped and the strands of the several layers so tightly interlocked and rigidly engaged that the terminal regions are substantially solidifled and rendered inert while the intermediate portion of the shaft is flexible; thus, aunitary shaft structure is provided wherein regions of desired flexibility and rigidity are embodied in a single unit structure.

Furthermore, a shaft terminal swaged in accordance with my invention affords a greater difl'erence between maximum and minimum diametrical dimensions of the swaged terminal region than may be found in shaft terminals swaged to provide a square or otherwise polygonal terminal region having flat faces as heretofore employed. As a consequence of the concaved recesses or troughs and interposed ridges or teeth, surfaces are afforded that engage corresponding surfaces in the socket in which the swaged terminal is to be engaged, that closely approximate radial planes, and the torque pressure effect therefore assumes a high point of emciency. This type of swaging also lends itself advantageously to attaching terminal fittings that may be either swaged thereon or secured by brazing, as may be desired.

Swaging of the terminal regions by the means herein proposed may be effected with equal efliciency by a much less pressure than is required to produce squared or polygonal terminal regions on shafts of equal diameter.

Although I have shown for illustration terminal tips having eight longitudinally disposed grooves or troughs and described them to be equally disposed circumfercntially about the outer surface of the shaft, they may be otherwise disposed or arranged in varied sequence ed through a flexible shaft casing having a minand number and be of a form other than a depression formed by a cylindriform projection of a die, and therefore, I do not desire to limit my invention to the precise details of construction and arrangement as herein specified, as it is obvious that various modifications may be made therein without departing from the essential features of my invention as defined in. the appended claims.

Having thus described my invention, I claim:

1. A coiled wire flexible shaft comprised of concentric members including a plurality of wire coils one snugly within another, with successive coils oppositely pitched so that each outer strand rests upon a plurality of turns of an inner strand, said shaft having a rigid fluted region comprising a plurality of longitudinal ridges in each coil thereof separated by circumferentially spaced inwardly curved grooves, each and every strand in each and every coil being curved inwardly so that it passes in arcuate form from one ridge into the next and is received in a groove of the adjacent inward member, and each individual strand being deformed opposite each strand of each adjacent coil to provide a compact mass in which the wires of successive coils interlock with one another and provide a solid structure constituting a rigid region in unitary relation with the rest of the flexible shaft structure and effective 'for preventing relative-movement of any strand.

2. A coiled wire flexible shaft comprised of concentric members including a plurality of wire coils one snugly within another, with successive coils oppositely pitched so that each outer strand rests upon a plurality of turns of an inner strand, said shaft at its end having arigid fluted region comprising a plurality of longitudinal ridges in each coil thereof separated by circumferentially spaced inwardlycurved grooves. each and every strand in each and every coil being curved inwardly so that it passes in arcuate form from one ridge into the next and is received in a groove of the adjacent inward member, and each individual strand being deformed opposite each strand of each adjacent coil to provide a compact mass in which the wires of successive coils,

interlock with one another and provide a solid structure constituting a rigid region in unitary relation with the rest of the flexible shaft structure at the end thereof and effective for preventing relative unwinding movement of any strand.

3. A coiled wire flexible shaft comprised of concentric members including a plurality of wire coils one snugly within another, with successive coils oppositely pitched so that each outer strand. rests upon a plurality of turns of an inner strand, said shaft having a rigid fluted region comprising a plurality of longitudinal ridges in each coil thereof separated by circumferentially spaced inwardly curved grooves, said ridges and grooves providing gear teeth at said rigid fluted region,

said teeth having an external diameter essentially identical with the diameter of the rest of the flexible shaft, each and every strand in each and every coil Ibeing curved inwardly so that it passes in arcuate form from one ridge into the.

next and is received in a groove of the adjacent inward member, and each individual strand being deformed opposite each strand of each adjacent coil to provide a compact mass in which the wires of successive coils interlock with one another and provide a solid structure constituting a rigid region in unitary relation with the rest of the flexible shaft structure and effective for preventing relative movement of any strand.

W'lLMER P. UHLER. 

